1. Field of the Invention
The present invention relates to the enhancement of gas, liquid or solid combustion reactions and/or to driving gas, liquid, or solid combustion chemical reactions.
2. Discussion of the Background
Combustion reactions are found in many different areas. Combustion reactions are found in the generation of power, for example, in internal combustion engines, turbines, jet engines, in fossil fueled electric utility plants, etc. Combustion reactions are also found in pollution control, for example, in the burning of pollutants produced by industrial processes.
Combustion reactions are however unfortunately not perfectly efficient. This results in loss of part of the energy contained in fuels, or in incomplete pollution control. There are also limits on how lean a fuel-air mixture can be reliably ignited and burned.
Increased flame speed can increase the efficiency of combustion reactions and reduce pollution. As an example, in an internal combustion engine, higher flame speed in lean mixtures could lead to a higher efficiency, better fuel economy, and reduced pollution.
Many different approaches are being pursued to increase combustion efficiency, including increasing turbulence,.sup.1 increasing the concentration of free radicals,.sup.2,3 applying electric fields,.sup.4 and microwaves..sup.5 Other approaches involve enhanced ignition such as plasma jet,.sup.6 torch,.sup.7 and laser ignition..sup.8,9 The direct injection of energetic particles, i.e., electrons, ions or neutral particles into a combustion chamber to stimulate combustion, to the inventor's knowledge, has however never been disclosed in the literature.
Numerous processes, including chemical and mechanical manufacturing processes, generate undesired pollutants. The optimal method of pollution control is to enhance the chemical reaction in such a way as to prevent the pollutants from being generated since such pollutants are difficult to deal with after they have been generated. Unfortunately, in most cases, this has so far not been possible.
Proposals have been made to filter effluent gases to remove pollutants, for example, by using a dust collector. Such approaches suffer from the fact that filtration systems are expensive, the filtration systems used are frequently incapable of completely removing the pollutants from effluent gases, and even if the pollutant is removed from an effluent gas, the problem of disposing of the pollutant remains.
It has been proposed that filtration of pollutants can be improved by irradiating effluent gases causing the polymerization of SO.sub.x and/or NO.sub.x contaminants contained therein to facilitate their removal. See Higo et al in U.S. Pat. Nos. 4,596,642 and 4,507,265. This approach however does not solve the problem of pollutant disposal since the SO.sub.x and/or NO.sub.x solids and/or mists collected still have to be disposed of. The Higo et al approach is also not fully satisfactory for the additional reason that the main object of both of these patents is to provide a complicated geometry to recover the polymerized pollutants.
Another area which has received attention is the development of systems promoting desired reactions. This is discussed for example by Matovich in U.S. Pat. Nos. 3,933,434 and 4,042,334. These two U.S. patents note that it would be useful to be able to carry out high temperature chemical reactions which heretofore have been impractical or only theoretically possible. A reactor is provided by these patents which utilizes radiation coupling as a thermal heat source. The reactor disclosed which uses electromagnetic radiation to heat a reaction is reportedly able to provide a thermal power density to the reaction site in excess of 10.sup.4 watts cm.sup.-2.
The reactor provided by U.S. Pat. Nos. 3,933,434 and 4,042,334 addresses high temperature chemical reactions, and more specifically pyrolysis reactions. This reactor provides an annular envelope containing an inert fluid which is substantially transparent to radiation. At least one reactant is passed through the core of the envelope along a predetermined path substantially coincident with the envelope axis, with the reactants being confined within this envelope. After reactant flow has started, radiant energy is directed through the envelope to coincide with at least a portion of the path of the reactants. This causes the absorption of a sufficient radiant energy in the core to raise the temperature of the reactant to a level required to initiate the desired chemical reaction.
In using this reactor, heat is supplied by radiation coupling rather than by convection and/or conduction. The configuration of this reactor permits that the temperature of the reactant stream be independent of both the temperature of the reactor wall and the conditions of the reaction stream. Its disclosed application resides in promoting pyrolysis reactions, e.g., transforming methane to carbon and dihydrogen.
This reactor uses electromagnetic radiation having a wavelength of from 100 microns to 10.sup.-2 microns for heating a reaction without actually modifying it. It is based on using electromagnetic radiation which limits the power density available to influence the reaction, and the configuration of the reactor provided precludes adaptation to various other areas where reaction enhancement would be useful.
Matovich discloses that the term "radiation" used in his patents is intended to encompass all forms of radiation, including high-energy or impacting nuclear particles. However, Matovich states that he knows of no manner in which high-energy or impacting nuclear particles can be used in accordance with his invention, and rather that black body or other electromagnetic radiation, particularly of wavelengths ranging from about 100 microns of 0.01 microns, should be used in his reactor. Matovich's system therefore uses electromagnetic radiation, and, only provides a method for directing heat onto a pyrolysis reaction. It does not provide a system for modifying and/or enhancing chemical reactions, and no combustion processes are mentioned in these patents.
There is therefore a strongly felt need for a method which would permit modifying and/or enhancing combustion processes so that these processes can be controlled and/or rendered more efficient with concomittant pollution control. Such a method would have applications in enhancing the combustion of materials, such as, fuel in internal combustion engines, electricity generation, controlling pollution, and driving reactions which are otherwise not possible.